Trenching machines are commonly employed to form a trench or ditch recessed into the ground for the purpose of laying underground pipe or cable that can be subsequently buried by refilling the trench above the laid pipe or cable with the soil or ground material originally removed by such a machine. Conventionally, a trencher uses an endless chain that is equipped with teeth or blades and entrained around a drive sprocket and an idler sprocket carried at opposite ends of a boom arm that is pivotally mounted to a frame of the trencher to swing a distal end of the boom arm upward and downward within a vertical plane. With the chain being driven along the periphery of the boom around the sprockets, the boom is lowered to bring the moving chain teeth into engagement with the ground surface to effectively cut thereinto and dig earth therefrom. The teeth or blades are often shaped to provide a cup or scoop like action that better carries the earth upward out of the ground as the teeth travel along the boom around the sprockets at the opposite ends thereof.
U.S. Pat. Nos. 3,087,854; 3,570,152; 4,159,360; 6,832,443 and U.S. Patent Application Publication Number 2007/0220783 assigned to The Charles Machine Works, Inc. relate to generally to trenching machines, and more particularly relate respectively to a variable speed gear reduction unit for a self-propelled trencher, a crumbing tool for connection to a trenching machine, an assembly for attachment of a tile chute or crumbing tool to the digging boom and mobile chassis of a trenching machine, a cutting chain for a trenching machine and an auger arrangement for a trenching assembly.
U.S. Pat. Nos. D266765 and 4,322,899 assigned to Midmark Corporation relate generally to trenching machines, and more particularly relate respectively to the ornamental design of a self-propelled walk-behind trenching machine and a hydraulic steering mechanism used in a self-propelled non-riding trenching machine.
Trenchers come in a variety of sizes and forms suitable for pipe or cable laying projects of varying scale. Self-propelled trenchers are available in ride-on units of varying sizes and smaller walk-behind units and incorporate drive systems operable to both propel the machine along the ground and drive the trenching or digging chain. Most of the smaller walk-behind units tend to suffer from poor traction relative to their larger ride-on counterparts. Trenching attachments are also available for removable installation on existing self-propelling work equipment of varying sizes, for example various tractors, loaders, walk behind or ride-on skid steers and other working machines. For example, a trenching attachment installed on a walk-behind skid steer may provide improved traction relative to a stand-alone walk-behind trencher. However, a conventional trenching attachment typically relies on a power take-off system of the vehicle or working machine on which it is installed to power its trenching or digging chain, and thus is limited in performance by the capabilities of this system. For example, the auxiliary hydraulic system of a walk behind mini-skid steer may not be capable of providing as much digging power to an attachment carried on the skid steer as could be produced using a stand-alone walk-behind gas-powered trencher.